Intermediate frequency transformer



May 21, 1963 HISAO MAEDA INTERMEDIATE FREQUENCY TRANSFORMER Filed May 11, 1960 by I I/5H0 MAEDA Ell 7 United States Patent 3,690,907 INTERMEDIATE FREQUENCY TRANSFGRlvlER Hisao Maeda, 13 hll0l-K0El, Minat'odin, 'loltyo-to, .lapan Filed May 11, 1960, Ser. No. 28,318 Claims priority, application iapan May 2:3, 1959 1 Claim. (Cl. Hit-7o} This invention relates to an intermediate-frequency transformer of improved construction for use in radio receivers of the superheterody-ne type.

It is an object of this invention to provide a new and improved intermediate frequency transformer having a built-in tuning capacitor.

It is another object of this invention to provide such an intermediate frequency transformer as stated above of simple and compact, yet strong construction.

The manner in which the foregoing as well as other objects and advantages may best be achieved will be understood more fully from a consideration of the following description of one embodiment of the invention, taken in conjunction with the accompanying drawing in which:

FIG. 1 is an elevational view, partly in section, showing the internal construction of one embodiment of this invention;

FIG. 2 is a bottom view of the embodiment of PEG. 1.

Referring to the drawing, the principal structural member of the intermediate frequency transformer of this invention is a base 2 made from an electrical insulation substance such as a phenol resin on which vertical support columns 1, 1 of arcuate shape in plan view are [rigidly fixed. The inner arcuate surfaces or" said columns 1, 1 lie on the same circle in diametrically opposed juxtaposition and have female screw threads on their surfaces. A spool-shaped, high-frequency magnetic core 4 about which is wound a coil 3 is disposed centrally on the said base 2 and is covered by a high-frequency magnetic cylinder 5, which has male screw threads on its outer peripheral surface, and which is screwed EQQ in and between the support columns 1, 1 by the engagement of the aforesaid male and female screw threads. A shield can 6 is adapted to enclose the aforedescribed main structural members 2 and 1, 1. Said shield can 6 has, on its top surface, a through opening 7, through which such a tool as a screw driver can be introduced and inserted into a slot 8 provided on the top of the aforesaid magnetic cylinder 5 to turn the said magnetic cylinder 5, thereby raising or lowering it and varying the inductance of the said coil 3.

It is a unique feature of the invention that the structure of the transformer contains a tuning capacitor 9 installed, in a space-economizing manner, in the bottom of the aforesaid base 2. This feature not only saves space, as compared with the arrangement according to the conventional art, wherein the intermediate frequency transformer and the tuning capacitor are installed separately, but also facilitates the installation of the two parts.

Since it is obvious that many changes and modifications can be made in the above described details Without departing from the nature and spirit of the invention, it is to be understood that the invention is not to be limited to the details described herein except as set forth in the appended claim.

Iclaim:

In an intermediate frequency transformer comprising, essentially, a spool-shaped, high-frequency magnetic core, about which is wound .a coil, and a high-frequency magnetic cylinder which covers, in the manner of a canopy, the said magnetic core, and which can be raised or lowered relative to the said magnetic core to vary the inductance of the said coil; the combination of said assembly with a tuning capacitor which is supported within the bottom of the base of said assembly.

References Cited in the file of this patent UNITED STATES PATENTS 

